Ce travail a été soutenu par le Conseil de recherches en génie du Canada Équipement, Découverte et subventions accélération à la découverte en sciences naturelles et attribués à JMBNRB reconnaît le soutien de la Carnegie Institution de programme de bourse post-doctorale Washington. Stephen Elardo est également remercié pour son aide avant le tournage avec la presse à piston-cylindre à la géophysique Lab.

Les auteurs ont rien à révéler.

Les résultats des expériences réalisées libre-inclusion en utilisant les protocoles décrits ici ont déjà été comparés avec les données de la littérature dans les références 29 (Os, Ir, Au), 30 (Re, Au) et 31 (Pt). Pt est le plus instructif dans la démonstration de l&#39;utilité de run-produits sans inclusion. Pour les expériences fonctionnent à faible f O 2, Ertel et al. 48 inclusions affecté à une origine stable et donc limité...

Accrétion terrestre est censé s&#39;être produit comme une série de collisions entre planétésimaux avec une composition en vrac chondritique, se terminant par une phase de géante impact pensait responsable de la formation de la lune 1,2. Le chauffage de la proto-Terre par des impacts et de la désintégration des isotopes de courte durée était suffisante pour provoquer une vaste fusion et la formation d&#39;un océan de magma ou étangs à travers lequel denses riches en Fe fond métalliques pourraient descendre. En arrivant au pied de l&#39;océan de magma, fondues métalliques rencontrent une limite rhéologique, décrochage, et subissent finale équilibre silicate de métal avant de finalement descendre à travers le manteau solide pour le noyau de plus en plus 2. En outre la communication chimique entre le métal et silicate phases comme fondue métallique traverse la partie solide du manteau est pensé pour être exclu en raison de la grande taille et la descente rapide de diapirs métalliques 3. Cette différenciation primaire de la Terre dans un noyau métallique et Mant silicatele est révélé aujourd&#39;hui par les deux observations géophysiques et géochimiques 4 - 6. L&#39;interprétation de ces observations pour obtenir des conditions plausibles pour l&#39;équilibre de silicate de métal à la base d&#39;un océan de magma, cependant, nécessite une base de données appropriée des résultats expérimentaux. Le manteau supérieur primitive (PUM) est un réservoir hypothétique comprenant le résidu de silicate de la formation de base et sa composition reflète donc le comportement des éléments traces pendant équilibre silicate de métal. Les oligo-éléments sont répartis entre le métal et silicate fond pendant noyau ségrégation sur la base de leur affinité géochimique. L&#39;ampleur de préférence un des éléments de la phase métallique peut être décrite par le coefficient de partage métal-silicate <img alt="Equation 1" src="/files/ftp_upload/52725/52725eq1.jpg" /><img alt="Equation 2" src="/files/ftp_upload/52725/52725eq2.jpg" /> (1) Où <img alt="Équation 3" src="/files/ftp_upload/52725/52725eq3.jpg" /> et <img alt="Equation 4" src="/files/ftp_upload/52725/52725eq4.jpg" /> désigner la concentration de l&#39;élément i en métal et silicate fondue respectivement. Les valeurs de <img alt="Equation 5" src="/files/ftp_upload/52725/52725eq5.jpg" /> &gt; 1 indiquent sidérophile comportement (fer-aimant) et ceux &lt;1 lithophile (rock-aimant) comportement. Les estimations de la composition spectacle de PUM que sidérophile éléments sont épuisés par rapport à chondrites 7, généralement considérés comme représentatifs de la composition en vrac de la Terre 6,8. Cet appauvrissement est due à la séquestration des éléments sidérophiles par le noyau, et pour les éléments réfractaires son ampleur devrait refléter directement les valeurs de <img alt="Equation 5" src="/files/ftp_upload/52725/52725eq5.jpg" /> . expériences de laboratoire cherchent donc à déterminer les valeurs de <img alt="Equation 5" src="/files/ftp_upload/52725/52725eq5.jpg" /> sur un range de pression (P), la température (T) et la fugacité de l&#39;oxygène (O 2 f) les conditions qui sont pertinents pour la séparation des métaux à partir de la base d&#39;un océan de magma. Les résultats de ces expériences peuvent alors être utilisées pour délimiter les régions de P - T - f O 2 l&#39;espace qui sont compatibles avec l&#39;abondance de PUM de plusieurs éléments sidérophiles (par exemple, 9 - 11). Les pressions et températures élevées pertinentes à un scénario magma de l&#39;océan peuvent être recréées en laboratoire en utilisant soit un piston-cylindre ou presse multi-enclume. Dispositif à cylindre et piston permet d&#39;accéder à une pression modérée (~ 2 GPa) et une température élevée (~ 2573 K) conditions, mais permet aux grands volumes d&#39;échantillon et une variété de matériaux de la capsule pour être facilement utilisés. Le taux de refroidissement rapide permet également trempe d&#39;une gamme de compositions thermofusibles à un verre de silicate, simplifiant ainsi l&#39;interprétation de la texture de la course-produits.L&#39;appareil multi-enclume emploie généralement des volumes d&#39;échantillons plus petits, mais avec des dessins d&#39;assemblage appropriés peut atteindre des pressions allant jusqu&#39;à ~ 27 GPa et des températures de ~ 3000 K. L&#39;utilisation de ces méthodes a permis des données de partitionnement pour beaucoup de l&#39;modérément et légèrement sidérophiles éléments soient recueillies sur une large gamme de conditions P - T. Prédictions de la composition de PUM basé sur ces données suggèrent équilibre silicate de métal produite dans des conditions de pression et de température moyenne de plus de ~ 29 GPa et 3000 K respectivement, bien que les valeurs exactes dépendent du modèle. Afin de tenir compte de l&#39;abondance de PUM de certains redox éléments sensibles (par exemple, V, Cr), le f O 2 est également pensé pour évoluer au cours de l&#39;accrétion de ~ 4 à 2 unités de log ci-dessous celle imposée par le fer et wüstite co-existante (FeO ) à des conditions équivalentes PT (le tampon de fer-wüstite) 12. Bien que l&#39;abondance de PUM de mtous les éléments de sidérophiles peuvent être comptabilisés par l&#39;équilibre de silicate de métal à la base d&#39;un océan de magma en profondeur, il a été difficile d&#39;évaluer si cette situation vaut également pour les éléments les plus hautement sidérophiles (HSE). L&#39;affinité des HSE extrême de fer-métal indiqué par une faible pression (P ~ 0,1 MPa) et la température (T &lt;1673 K) expériences suggèrent la terre de silicate doit être fortement appauvri en ces éléments. Les estimations de la teneur HSE pour PUM, cependant, indiquent qu&#39;une déplétion modérée par rapport à chondrite (Figure 1). Une solution couramment posée à l&#39;excès apparent HSE est que la Terre a connu une fin de l&#39;accrétion de matière chondritique à la suite de la formation de base-13. Ce matériau fin-accrétion aurait mélangé avec le PUM et des concentrations élevées HSE mais a eu un effet négligeable sur les éléments les plus abondants. Alternativement, il a été suggéré que la nature extrêmement sidérophile de HSE indiqué par une faible P </em&gt; - T expériences ne persistent pas dans les conditions PT élevés présents lors de la formation de base-14,15. Afin de tester ces hypothèses, les expériences doivent être menées afin de déterminer la solubilité et métal-silicate partitionnement du HSE dans des conditions appropriées. La contamination de la partie silicate de run-produits trempés dans cependant de nombreuses études antérieures, a compliqué l&#39;analyse run-produit et occulté les véritables coefficients de partition pour HSE entre métal et silicates fondus. Dans les expériences de séparation où les HSE sont présents à des niveaux appropriés à la nature de concentration, l&#39;extrême préférence de ces éléments pour Fe-métal empêche leur mesure dans le liquide silicaté. Pour contourner ce problème, des mesures de solubilité sont réalisées dans laquelle la masse fondue de silicate est saturé dans la HSE d&#39;intérêt et les valeurs de <img alt="Equation 5" src="/files/ftp_upload/52725/52725eq5.jpg" /> sont calculées en utilisant le formalisme de Borisov et. 16 al. Silicate trempé run-produits de HSE expériences de solubilité réalisées à des conditions de réduction, cependant, affichent souvent des preuves de contamination par dispersé HSE ± Fe inclusions 17. Malgré la quasi-omniprésence de ces inclusions en basse f O 2 expériences contenant Pt, Ir, Os, Re et Ru, (par exemple, 18 - 27), il ya une variabilité notable entre les études dans leur présentation de texture; comparer par exemple référence 22 et 26. Bien qu&#39;il ait été démontré que les inclusions peuvent se former qui sont dans une phase stable aux conditions d&#39;exécution d&#39;une expérience de 28, cela ne fait pas obstacle à la formation d&#39;inclusions que l&#39;échantillon est trempé. L&#39;incertitude entourant l&#39;origine des inclusions rend le traitement des résultats d&#39;analyse difficile, et a conduit à l&#39;ambiguïté sur la véritable solubilité du HSE en silicate réduit fond. run-produits sans-inclusion sont nécessaires pour évaluerque des études ont adopté une approche analytique qui donne des concentrations de HSE dissous précises. Des progrès considérables dans la suppression de la formation de métal-inclusions à des conditions réductrices a été démontré dans des expériences en utilisant un appareil à piston-cylindre, dans laquelle la conception de l&#39;échantillon a été modifiée à partir d&#39;études précédentes en ajoutant soit Au ou Si les matériaux de départ de 29 à 31. L&#39;addition de Au ou de Si élémentaire pour les matières de départ, respectivement, modifie la géométrie de l&#39;échantillon ou f O 2 évolution de l&#39;expérience. Ces méthodes ont pour but de supprimer la formation de l&#39;inclusion de métal en modifiant le moment de la HSE en diffusion par rapport à la réduction de l&#39;échantillon, et sont discutés dans Bennett et al. 31. Contrairement à certaines tentatives précédentes pour nettoyer la fonte de silicate d&#39;inclusions, telles que l&#39;équilibrage assistée mécaniquement et le piston-cylindre centrifugation, le présent protocole peut être mis en œuvre sans appar spécialiséeatus et est adapté pour des expériences de haute PT. Décrit en détail ici est une approche fondée sur piston-cylindre pour déterminer la solubilité de Re, Os, Ir, Ru, Pt et Au en liquide silicaté à haute température (&gt; 1873 K), 2 GPa et une f O 2 similaire à celle de le tampon de fer-wüstite. L&#39;application d&#39;un modèle expérimental similaire peut également se révéler succès dans les expériences HSE à d&#39;autres pressions, en fournissant les relations de phase requis, propriétés de mouillage et les relations cinétiques persister dans les conditions choisies. Les données existantes sont cependant insuffisantes pour prédire si notre conception de l&#39;échantillon sera couronnée de succès à des pressions correspondant à un océan de magma en profondeur. Aussi décrit est une approche générale utilisée pour déterminer modérément et légèrement élément sidérophile (MSE et SSE respectivement) partitionnement en utilisant un dispositif multi-enclume. Extension de l&#39;ensemble de données sans-inclusion pour HSE à haute pression est susceptible d&#39;employer des méthodes multi-enclume similaires. Togéther, ces procédures constituent un moyen de contraindre les deux conditions de base-ségrégation et les étapes de l&#39;accrétion terrestre.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>G10 Epoxy/Fiberglass Sheet</td>
			<td>Accurate plastics, Inc.</td>
			<td>GEES.020N.3648</td>
			<td></td>
		</tr>
		<tr>
			<td>Powdered starting materials- -Oxides, metals, carbonates</td>
			<td>Alfa Aesar</td>
			<td>Specific to desired experiment</td>
			<td></td>
		</tr>
		<tr>
			<td>Castable 2-part MgO ceramic</td>
			<td>Aremco</td>
			<td>Ceramcast - 584</td>
			<td></td>
		</tr>
		<tr>
			<td>PTFE Dry Lubricant</td>
			<td>Camie-Campbell</td>
			<td>2000 TFE-Coat</td>
			<td></td>
		</tr>
		<tr>
			<td>Graphite resistance heaters</td>
			<td>Carbone of America (Now owned by Mersen USA)</td>
			<td>Custom Order</td>
			<td></td>
		</tr>
		<tr>
			<td>Barium Carbonate</td>
			<td>Chemical Products Corporation</td>
			<td>Custom Order</td>
			<td>Calcined free-flowing (CFF) grade</td>
		</tr>
		<tr>
			<td>C-Type Thermocouple Wire (W26%Re, W5%Re)</td>
			<td>Concept Alloys</td>
			<td>N/A</td>
			<td>~0.25 mm diameter is suitable for most experiments</td>
		</tr>
		<tr>
			<td>Zirconia Cement</td>
			<td>Cotronics; Resbond 940 2-part cement</td>
			<td>N/A</td>
			<td>Use 100 parts powder for every 25 to 28 parts activator</td>
		</tr>
		<tr>
			<td>Polyvinyl Acetate (PVA) Glue</td>
			<td>e.g Bostik</td>
			<td>N/A</td>
			<td>Often sold as &#39;white glue&#39;</td>
		</tr>
		<tr>
			<td>Cyanoacrylate Glue</td>
			<td>e.g Krazy Glue/Loctite</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Piston cylinder pressure vessel and WC piston</td>
			<td>Hi-Quality Carbide Tooling Inc.</td>
			<td>Custom Order</td>
			<td></td>
		</tr>
		<tr>
			<td>Silica Glass Tubing</td>
			<td>Quartz Plus</td>
			<td>Custom Order</td>
			<td></td>
		</tr>
		<tr>
			<td>Crushable ZrO2 tubes</td>
			<td>Saint-Gobain</td>
			<td>Custom Order</td>
			<td></td>
		</tr>
		<tr>
			<td>Crushable MgO rods and tubes</td>
			<td>Saint-Gobain</td>
			<td>Custom Order</td>
			<td></td>
		</tr>
		<tr>
			<td>WC cubes for multi-anvil experiments</td>
			<td>Tungaloy</td>
			<td>Custom Order</td>
			<td>Cubes are grade-F WC alloy</td>
		</tr>
		<tr>
			<td>Single hole alumina tube for multi-anvil thermocouple</td>
			<td>Vesuvius McDanel</td>
			<td>AXS071730-04-06</td>
			<td></td>
		</tr>
		<tr>
			<td>4-hole alumina tube for piston cylinder thermocouple</td>
			<td>Vesuvius McDanel</td>
			<td>AXF1159--07-12&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>4-hole alumina tube for multi-anvil thermocouple</td>
			<td>Vesuvius McDanel</td>
			<td>AXF1159-04-06</td>
			<td></td>
		</tr>
	</tbody>
</table>

metal-silicate partitioning at high pressure and temperature: experimental methods and a protocol to suppress highly siderophile element inclusions

Estimates of the primitive upper mantle (PUM) composition reveal a depletion in many of the siderophile (iron-loving) elements, thought to result from their extraction to the core during terrestrial accretion. Experiments to investigate the partitioning of these elements between metal and silicate melts suggest that the PUM composition is best matched if metal-silicate equilibrium occurred at high pressures and temperatures, in a deep magma ocean environment. The behavior of the most highly siderophile elements (HSEs) during this process however, has remained enigmatic. Silicate run-products from HSE solubility experiments are commonly contaminated by dispersed metal inclusions that hinder the measurement of element concentrations in the melt. The resulting uncertainty over the true solubility and metal-silicate partitioning of these elements has made it difficult to predict their expected depletion in PUM. Recently, several studies have employed changes to the experimental design used for high pressure and temperature solubility experiments in order to suppress the formation of metal inclusions. The addition of Au (Re, Os, Ir, Ru experiments) or elemental Si (Pt experiments) to the sample acts to alter either the geometry or rate of sample reduction respectively, in order to avoid transient metal oversaturation of the silicate melt. This contribution outlines procedures for using the piston-cylinder and multi-anvil apparatus to conduct solubility and metal-silicate partitioning experiments respectively. A protocol is also described for the synthesis of uncontaminated run-products from HSE solubility experiments in which the oxygen fugacity is similar to that during terrestrial core-formation. Time-resolved LA-ICP-MS spectra are presented as evidence for the absence of metal-inclusions in run-products from earlier studies, and also confirm that the technique may be extended to investigate Ru. Examples are also given of how these data may be applied.

Les exemples suivants et les débats se concentrent sur ​​des expériences pour déterminer HSE solubilité dans silicate fond à faible f O 2. Pour des exemples détaillés de la façon dont MSE et les données de partitionnement de l&#39;ESS à partir d&#39;expériences multi-enclume peuvent être utilisés pour contraindre le P - T - f O 2 conditions de base ségrégation de métal, le lecteur est renvoyé aux références 9 -. 11 Figure...

Watch this Scientific Journal Video about Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions at JoVE.co

Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions

We present a procedure to determine the metal-silicate partitioning of siderophile elements, emphasizing techniques that suppress the formation of metal inclusions in experiments for the noble metals. The results of these experiments are used to demonstrate the effect of core-formation on the highly siderophile element composition of the mantle.

partitionnement de Metal-silicate à haute pression et température: méthodes expérimentales et un protocole à réprimer fortement sidérophile Element Inclusions

Estimates of the primitive upper mantle (PUM) composition reveal a depletion in many of the siderophile (iron-loving) elements, thought to result from ...

metal-silicate-partitioning-at-high-pressure-temperature-experimental

Research

Education

JoVE Journal

JoVE Core

Chemistry

Chemical Equilibrium

SCIENTISTS IN ACTION

12.4K vues.  University of Toronto. We present a procedure to determine the metal-silicate partitioning of siderophile elements, emphasizing techniques that suppress the formation of metal inclusions in experiments for the noble metals. The results of these experiments are used to demonstrate the effect of core-formation on the highly siderophile element composition of the mantle.

Vidéo: Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems

The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. Specifically, the sapphire cell enables visual data collection from multiple loadings to solve a set of material balances to precisely determine phase composition. Ternary phase diagrams can then be established to determine the proportion of each component in each phase at a given condition. In principle, any ternary system can be studied although ternary systems (gas-liquid-liquid) are the specific examples discussed herein. For instance, the ternary THF-Water-CO2 system was studied at 25 and 40&#160;&#176;C and is described herein. Of key importance, this technique does not require sampling. Circumventing the possible disturbance of the system equilibrium upon sampling, inherent measurement errors, and technical difficulties of physically sampling under pressure is a significant benefit of this technique. Perhaps as important, the sapphire cell also enables the direct visual observation of the phase behavior. In fact, as the CO2 pressure is increased, the homogeneous THF-Water solution phase splits at about 2 MPa. With this technique, it was possible to easily and clearly observe the cloud point and determine the composition of the newly formed phases as a function of pressure.
The data acquired with the sapphire cell technique can be used for many applications. In our case, we measured swelling and composition for tunable solvents, like gas-expanded liquids, gas-expanded ionic liquids and Organic Aqueous Tunable Systems (OATS)1-4. For the latest system, OATS, the high-pressure sapphire cell enabled the study of (1) phase behavior as a function of pressure and temperature, (2) composition of each phase (gas-liquid-liquid) as a function of pressure and temperature and (3) catalyst partitioning in the two liquid phases as a function of pressure and composition. Finally, the sapphire cell is an especially effective tool to gather accurate and reproducible measurements in a timely fashion.

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems

The high pressure sapphire cell apparatus is a unique tool to study, without sampling, phase behavior under a wide range of pressures. Using a cathetometer, very precise volume measurements can be recorded to measure liquid expansion and phase composition. Thus, this synthetic method enables the study of (1) phase equilibria of multi-component mixtures and (2) the partition behavior of catalyst or model compounds as a function of pressure.

Haute pression portable Sapphire pour les mesures de phase équilibres de CO<sub&gt; 2</sub&gt; / / Water Systems organiques

The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. ...

Recherche

Chimie

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel &#945;-diimine ethylene polymerization catalyst. Initial polymerizations with the catalyst lead to optimized reaction conditions, including catalyst concentration, ethylene pressure and reaction time. Using gas-uptake data for these reactions, a procedure to calculate the initial rate of propagation (kp) is presented. Using the optimized conditions, the ability of the nickel &#945;-diimine polymerization catalyst to undergo chain transfer with diethylzinc (ZnEt2) during ethylene polymerization was investigated. A procedure to assess the ability of the catalyst to undergo chain transfer (from molecular weight and 13C NMR data), calculate the degree of chain transfer, and calculate chain transfer rates (ke) is presented.

A protocol for the high-throughput analysis of polymerization catalyst, chain transfer polymerizations, polyethylene characterization, and reaction kinetic analysis is presented.

Les polymérisations de l&#39;éthylène en utilisant des réacteurs à pression parallèles et une analyse cinétique de polymérisation de transfert de chaîne

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel ...

Preparation of Carbon Nanosheets at Room Temperature

Amphiphilic molecules equipped with a reactive, carbon-rich "oligoyne" segment consisting of conjugated carbon-carbon triple bonds self-assemble into defined aggregates in aqueous media and at the air-water interface. In the aggregated state, the oligoynes can then be carbonized under mild conditions while preserving the morphology and the embedded chemical functionalization. This novel approach provides direct access to functionalized carbon nanomaterials. In this article, we present a synthetic approach that allows us to prepare hexayne carboxylate amphiphiles as carbon-rich siblings of typical fatty acid esters through a series of repeated bromination and Negishi-type cross-coupling reactions. The obtained compounds are designed to self-assemble into monolayers at the air-water interface, and we show how this can be achieved in a Langmuir trough. Thus, compression of the molecules at the air-water interface triggers the film formation and leads to a densely packed layer of the molecules. The complete carbonization of the films at the air-water interface is then accomplished by cross-linking of the hexayne layer at room temperature, using UV irradiation as a mild external stimulus. The changes in the layer during this process can be monitored with the help of infrared reflection-absorption spectroscopy and Brewster angle microscopy. Moreover, a transfer of the carbonized films onto solid substrates by the Langmuir-Blodgett technique has enabled us to prove that they were carbon nanosheets with lateral dimensions on the order of centimeters.

We present the synthesis of an amphiphilic hexayne and its use in the preparation of carbon nanosheets at the air-water interface from a self-assembled monolayer of these reactive, carbon-rich molecular precursors.

Préparation de nanofeuillets carbone à température ambiante

Amphiphilic molecules equipped with a reactive, carbon-rich "oligoyne" segment consisting of conjugated carbon-carbon triple bonds self-assemble into ...

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of trifluoromethoxylated aromatic compounds remains a formidable challenge in organic synthesis. Conventional approaches often suffer from poor substrate scope, or require use of highly toxic, difficult-to-handle, and/or thermally labile reagents. Herein, we report a user-friendly protocol for the synthesis of methyl 4-acetamido-3-(trifluoromethoxy)benzoate using 1-trifluoromethyl-1,2-benziodoxol-3(1H)-one (Togni reagent II). Treating methyl 4-(N-hydroxyacetamido)benzoate (1a) with Togni reagent II in the presence of a catalytic amount of cesium carbonate (Cs2CO3) in chloroform at RT afforded methyl 4-(N-(trifluoromethoxy)acetamido)benzoate (2a). This intermediate was then converted to the final product methyl 4-acetamido-3-(trifluoromethoxy)benzoate (3a) in nitromethane at 120 &#176;C. This procedure is general and can be applied to the synthesis of a broad spectrum of ortho-trifluoromethoxylated aniline derivatives, which could serve as useful synthetic building blocks for the discovery and development of new pharmaceuticals, agrochemicals, and functional materials.

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

An operationally simple procedure for the synthesis of ortho-trifluoromethoxylated aniline derivatives via a two-step sequence of O-trifluoromethylation of N-aryl-N-hydroxyacetamide followed by thermally induced intramolecular OCF3-migration is reported.

Protocole pour la synthèse du<em&gt; Ortho</em&gt; dérivés de l&#39;aniline -trifluoromethoxylated

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of ...

Rapid High-throughput Species Identification of Botanical Material Using Direct Analysis in Real Time High Resolution Mass Spectrometry

We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, and that these chemical fingerprints can be used for plant species identification. The mass spectral data can be acquired rapidly and in a high throughput manner without the need for sample extraction, derivatization or pH adjustment steps. The use of this technique bypasses challenges presented by more conventional techniques including lengthy chromatography analysis times and resource intensive methods. The high throughput capabilities of the direct analysis in real time-high resolution mass spectrometry protocol, coupled with multivariate statistical analysis processing of the data, provide not only class characterization of plants, but also yield species and varietal information. Here, the technique is demonstrated with two psychoactive plant products, Mitragyna speciosa (Kratom) and Datura (Jimsonweed), which were subjected to direct analysis in real time-high resolution mass spectrometry followed by statistical analysis processing of the mass spectral data. The application of these tools in tandem enabled the plant materials to be rapidly identified at the level of variety and species.

A method for species identification of botanical material by direct analysis in real time-high resolution mass spectrometry and multivariate statistical analysis is presented.

Rapid à haut débit Identification des espèces de matériel botanique Utilisation de l&#39;analyse directe en temps réel Résolution Spectrométrie de Masse Haute

We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, ...

High Pressure Single Crystal Diffraction at PX^2

In this report we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell (DAC) at the GSECARS 13-BM-C beamline at the Advanced Photon Source. The DAC program at 13-BM-C is part of the Partnership for Extreme Xtallography (PX^2) project. BX-90 type DACs with conical-type diamond anvils and backing plates are recommended for these experiments. The sample chamber should be loaded with noble gas to maintain a hydrostatic pressure environment. The sample is aligned to the rotation center of the diffraction goniometer. The MARCCD area detector is calibrated with a powder diffraction pattern from LaB6. The sample diffraction peaks are analyzed with the ATREX software program, and are then indexed with the RSV software program. RSV is used to refine the UB matrix of the single crystal, and with this information and the peak prediction function, more diffraction peaks can be located. Representative single crystal diffraction data from an omphacite (Ca0.51Na0.48)(Mg0.44Al0.44Fe2+0.14Fe3+0.02)Si2O6 sample were collected. Analysis of the data gave a monoclinic lattice with P2/n space group at 0.35 GPa, and the lattice parameters were found to be: a = 9.496 &#177;0.006 &#197;, b = 8.761 &#177;0.004 &#197;, c = 5.248 &#177;0.001 &#197;, &#946; = 105.06 &#177;0.03&#186;, &#945; = &#947; = 90&#186;.

In this report, we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell at the GSECARS 13-BM-C beamline at the Advanced Photon Source. ATREX and RSV programs are used to analyze the data.

High Pressure Monocristal Diffraction PX ^ 2

In this report we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell (DAC) at the ...

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose of efficiently driving non-equilibrium chemistry is discussed. The advantage of a flowing plasma reactor is that continuous chemical processes can be driven with the flexibility of startup times in the seconds timescale. The plasma approach is generically suitable for conversion/activation of stable molecules such as CO2, N2 and CH4. Here the reduction of CO2 to CO is used as a model system: the complementary diagnostics illustrate how a baseline thermodynamic equilibrium conversion can be exceeded by the intrinsic non-equilibrium from high vibrational excitation. Laser (Rayleigh) scattering is used to measure the reactor temperature and Fourier Transform Infrared Spectroscopy (FTIR) to characterize in situ internal (vibrational) excitation as well as the effluent composition to monitor conversion and selectivity.

This article describes a flowing microwave reactor that is used to drive efficient non-equilibrium chemistry for the application of conversion/activation of stable molecules such as CO2, N2 and CH4. The goal of the procedure described here is to measure the in situ gas temperature and gas conversion.

Plasma à micro-ondes non équilibré pour une chimie à haute température efficace

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose ...

A Straightforward Method for Glucosinolate Extraction and Analysis with High-pressure Liquid Chromatography (HPLC)

Glucosinolates are a well-studied and highly diverse class of natural plant compounds. They play important roles in plant resistance, rapeseed oil quality, food flavoring, and human health. The biological activity of glucosinolates is released upon tissue damage, when they are mixed with the enzyme myrosinase. This results in the formation of pungent and toxic breakdown products, such as isothiocyanates and nitriles. Currently, more than 130 structurally different glucosinolates have been identified. The chemical structure of the glucosinolate is an important determinant of the product that is formed, which in turn determines its biological activity. The latter may range from detrimental (e.g., progoitrin) to beneficial (e.g., glucoraphanin). Each glucosinolate-containing plant species has its own specific glucosinolate profile. For this reason, it is important to correctly identify and reliably quantify the different glucosinolates present in brassicaceous leaf, seed, and root crops or, for ecological studies, in their wild relatives. Here, we present a well-validated, targeted, and robust method to analyze glucosinolate profiles in a wide range of plant species and plant organs. Intact glucosinolates are extracted from ground plant materials with a methanol-water mixture at high temperatures to disable myrosinase activity. Thereafter, the resulting extract is brought onto an ion-exchange column for purification. After sulfatase treatment, the desulfoglucosinolates are eluted with water and the eluate is freeze-dried. The residue is taken up in an exact volume of water, which is analyzed by high-pressure liquid chromatography (HPLC) with a photodiode array (PDA) or ultraviolet (UV) detector. Detection and quantification are achieved by conducting comparisons of the retention times and UV spectra of commercial reference standards. The concentrations are calculated based on a sinigrin reference curve and well-established response factors. The advantages and disadvantages of this straightforward method, when compared to faster and more technologically advanced methods, are discussed here.

A Straightforward Method for Glucosinolate Extraction and Analysis with High-pressure Liquid Chromatography HPLC

Here, we describe in great detail an established and robust protocol for the extraction of glucosinolates from ground plant materials. After an on-column sulfatase treatment of the extracts, the desulfoglucosinolates are eluted and analyzed by high-pressure liquid chromatography.

Une méthode simple pour l&#39;extraction et l&#39;analyse glucosinolates avec haute pression chromatographie liquide (HPLC)

Glucosinolates are a well-studied and highly diverse class of natural plant compounds. They play important roles in plant resistance, rapeseed oil ...

A Convenient Method for Extraction and Analysis with High-Pressure Liquid Chromatography of Catecholamine Neurotransmitters and Their Metabolites

The extraction and analysis of catecholamine neurotransmitters in biological fluids is of great importance in assessing nervous system function and related diseases, but their precise measurement is still a challenge. Many protocols have been described for neurotransmitter measurement by a variety of instruments, including high-pressure liquid chromatography (HPLC). However, there are shortcomings, such as complicated operation or hard-to-detect multiple targets, which cannot be avoided, and presently, the dominant analysis technique is still HPLC coupled with sensitive electrochemical or fluorimetric detection, due to its high sensitivity and good selectivity. Here, a detailed protocol is described for the pretreatment and detection of catecholamines with high pressure liquid chromatography with electrochemical detection (HPLC-ECD) in real urine samples of infants, using electrospun composite nanofibers composed of polymeric crown ether with polystyrene as adsorbent, also known as the packed-fiber solid phase extraction (PFSPE) method. We show how urine samples can be easily precleaned by a nanofiber-packed solid phase column, and how the analytes in the sample can be rapidly enriched, desorbed, and detected on an ECD system. PFSPE greatly simplifies the pretreatment procedures for biological samples, allowing for decreased time, expense, and reduction of the loss of targets. 
Overall, this work illustrates a simple and convenient protocol for solid-phase extraction coupled to an HPLC-ECD system for simultaneous determination of three monoamine neurotransmitters (norepinephrine (NE), epinephrine (E), dopamine (DA)) and two of their metabolites (3-methoxy-4-hydroxyphenylglycol (MHPG) and 3,4-dihydroxy-phenylacetic acid (DOPAC)) in infants' urine. The established protocol was applied to assess the differences of urinary catecholamines and their metabolites between high-risk infants with perinatal brain damage and healthy controls. Comparative analysis revealed a significant difference in urinary MHPG between the two groups, indicating that the catecholamine metabolites may be an important candidate marker for early diagnosis of cases at risk for brain damage in infants.

We present a convenient solid-phase extraction coupled to high-pressure liquid chromatography (HPLC) with electrochemical detection (ECD) for simultaneous determination of three monoamine neurotransmitters and two of their metabolites in infants' urine. We also identify the metabolite MHPG as a potential biomarker for the early diagnosis of brain damage for infants.

Une méthode pratique pour l’Extraction et analyse par chromatographie liquide à haute pression des neurotransmetteurs catécholamines et de leurs métabolites

The extraction and analysis of catecholamine neurotransmitters in biological fluids is of great importance in assessing nervous system function and ...

Experimental Methods for Efficient Solar Hydrogen Production in Microgravity Environment

Long-term space flights and cis-lunar research platforms require a sustainable and light life-support hardware which can be reliably employed outside the Earth's atmosphere. So-called 'solar fuel' devices, currently developed for terrestrial applications in the quest for realizing a sustainable energy economy on Earth, provide promising alternative systems to existing air-revitalization units employed on the International Space Station (ISS) through photoelectrochemical water-splitting and hydrogen production. One obstacle for water (photo-) electrolysis in reduced gravity environments is the absence of buoyancy and the consequential, hindered gas bubble release from the electrode surface. This causes the formation of gas bubble froth layers in proximity to the electrode surface, leading to an increase in ohmic resistance and cell-efficiency loss due to reduced mass transfer of substrates and products to and from the electrode. Recently, we have demonstrated efficient solar hydrogen production in microgravity environment, using an integrated semiconductor-electrocatalyst system with p-type indium phosphide as the light-absorber and a rhodium electrocatalyst. By nanostructuring the electrocatalyst using shadow nanosphere lithography and thereby creating catalytic 'hot spots' on the photoelectrode surface, we could overcome gas bubble coalescence and mass transfer limitations and demonstrated efficient hydrogen production at high current densities in reduced gravitation. Here, the experimental details are described for the preparations of these nanostructured devices and further on, the procedure for their testing in microgravity environment, realized at the Bremen Drop Tower during 9.3 s of free fall.

Efficient solar-hydrogen production has recently been realized on functionalized semiconductor-electrocatalyst systems in a photoelectrochemical half-cell in microgravity environment at the Bremen Drop Tower. Here, we report the experimental procedures for manufacturing the semiconductor-electrocatalyst device, details of the experimental set-up in the drop capsule and the experimental sequence during free fall.

Méthodes expérimentales pour une production efficace d'hydrogène solaire dans l'environnement de microgravité

Long-term space flights and cis-lunar research platforms require a sustainable and light life-support hardware which can be reliably employed outside the ...